1. Field of the Invention
The present invention relates generally to filtration systems and the disposal of radioactive waste. In particular, the present invention relates to a filtration system for concentrating radioactive particles from a refueling cavity, spent fuel pool or other water volume where small particles must be removed from the water for disposal, improving water clarity, reducing radiation level, or other reasons.
2. Description of the Related Art
Commercial nuclear reactor power plants have various water volumes that are subject to contamination with radioactive debris particulate. These water volumes include, for example, the refueling cavity and the spent fuel pool. The particulate contained in these water volumes typically includes "crud" (corrosion products) and "cutting fines" that may range in size from sub-micron to several millimeters in cross-section. The cutting fines are often mixed with other non-radioactive particles that are byproducts of a cutting operation, such as abrasive or electrode materials.
There are several reasons that the radioactive debris particulate needs to be removed from the various water volumes in the nuclear reactor power plants from time-to-time. For example, the small particles often must be removed from the water for disposal, to improve water clarity, and/or to reduce the radiation level of the water volume. Therefore, there is a need for a system that provides efficient filtration, concentration, and transport to collection canisters of the radioactive particles from the various water volumes.
Vendors performing dismantling operations in the commercial nudear power decommissioning business have experienced significant problems with refueling cavity contamination, increased costs for disposal of waste, and dose rates to personnel that are not As Low As is Reasonably Achievable ("ALARA"). Contamination issues have been partly due to the lack of a control volume and closed-loop filtration system. High waste disposal costs have resulted from a failure to segregate and concentrate the particles by a separate means, rather than relying on the use of conventional cartridge-type filters alone. Minimizing the quantity of cartridge filters, which represent an increased volume of secondary waste, will reduce disposal costs. Dose rates to personnel can be reduced by controlling contamination through a closed loop system.